In the earliest available builds of Yume Nikki, the gate on a high ledge in Block World leads to a room colloquially known as the "Toriningen's Bed" event; it is present in Version 0.04, 0.06, and presumably 0.05, but because Versions 0.00 to 0.03 are not publicly available (as is 0.05), it is unknown if the Toriningen's Bed event was added in Version 0.04 or if it was present in prior builds.

This room consists solely of a long walkway leading to a bed. Entering it causes a lunatic Toriningen to spawn at the entrance of the walkway; because the hallway is only one tile wide, there is no way of avoiding it, and once it catches Madotsuki, she is transported to an out of bounds portion of Footprint Path A, rendering her immobile until she wakes up or teleports back to the Nexus with the Eye Palm effect. Version 0.06 revises the area so that it uses Block World's background music, played at 50% speed, instead of Eyeball World's background music.

In Version 0.07, the Toriningen's Bed event is removed, and the gate leading to it now leads to the White Desert; this change is retained in Version 0.10. Discounting the unused "NASU Link" event in Version 0.09, this is the only known event that was removed in a later update.

The earliest builds of the game only contained 20 effects, missing the Witch, Oni, Squish-Squish, and Traffic Light. These four were not added until Version 0.05, as evidenced by the changelog provided in both the game's README file and Kikiyama's official website.

Of particular note is the Squish-Squish effect, which is provided by interacting with an amorphous, blue-gray figure with a single, large eye. In Version 0.06 (the earliest available build to feature all 24 effects), the figure was present in a shack in the Barracks Settlement that Madotsuki could not enter in previous versions. In Version 0.08, the figure is moved to FC World B; however, a copy of it is still present in its original location in the Barracks Settlement, where it is being fed on by the newly added Seahorse. In Version 0.09, the Seahorse's design is updated to change its skin from purple to orange and add four hornlike structures to the top of its head. Version 0.10 removes the version of the figure that the Seahorse fed on.

This sequence of events gives the impression that the Seahorse's development was a direct result of feeding on the figure, thus providing the only known instance of the game's updates appearing to convey a narrative within the Dream World.

Hogwarts Legacy is notable for introducing the first transgender character in the Harry Potter franchise in the form of Sirona Ryan, the owner of the Three Broomsticks pub who outright tells the player that it took her classmates "a second to realize I was actually a witch, not a wizard". This drew attention as the creator of the Harry Potter franchise, J.K. Rowling, has generated controversy over the years by making comments that many have criticized as transphobic. It is worth noting that while it was known prior to release that she would receive profits from the game's sales leading many fans to boycott the game, she had no involvement in its development. In regards to the inclusion, the developers stated:


However, after the character was revealed, several fans further complained that the name Sirona Ryan rendered the inclusion of a transgender character tone deaf and continued promoting the boycott. The name "Sirona" originates from the Celtic goddess of healing and rebirth and is symbolized with imagery of snakes (animals that shed their skin) and eggs (where many birds, fish and reptiles among other animals emerge from after incubating). Despite being a feminine name, they claimed to perceive it as a male-presenting name due to that variant of the name containing and potentially being shortened to "Sir", while also pointing out that the surname "Ryan" was a masculine name and an anglicized form instead of using the less common authentic Gaelic name "Riain" alongside "Sirona", appearing as an unintentional pun: "Sir Ryan". Despite these complaints, the boycott turned out to be a failure as Hogwarts Legacy became commercially successful, selling over 12 million copies in its first two weeks of release and going on to sell double that amount by the end of 2023.

The game is notable for two puzzles considered by fans and critics to be among the best and worst ever made for an adventure game.

The puzzle "Le Serpent Rouge" ("The Red Snake") involves decoding torn-up poem stanzas by hunting for information and solving geometric mapping puzzles. This puzzle was widely praised for its overarching complexity and intriguing nature regardless of the player's interest in the real-life mysteries of Rennes-le-Château, a Southern French commune crucial to the game's plot that has been covered in various books and conspiracy theories. The poem was originally included in the "Secret Files of Henri Lobineau", a 1967 dossier about the fraternal organization Priory of Sion, and was modified to make the puzzle solvable. Lead designer Jane Jensen called it her favorite and most challenging puzzle, designing it around the game's fully controllable 3D camera.

Meanwhile, a puzzle designed by producer Steven Hill was disliked internally and meant to be replaced with a puzzle by Jensen, but time constraints forced it to be left in the game. It starts with Gabriel Knight discovering that his friend Detective Mosely arrived in France the night before in a tour group and is scheduled to rent a motorcycle that day, so Knight goes to rent one himself. The nearsighted rental stand clerk requires a passport to confirm arrivals, revealing that he only has a bike saved for Mosely and a cheap scooter. To get the bike, Knight plans to disguise himself as Mosely by Spoiler:stealing his coat and passport, and hiding his long blonde hair in a hat to pretend he has Mosely's short brown hair underneath, albeit with a ponytail. He then draws a mustache on Mosely's photo to obscure their facial differences, goes to a shed, puts masking tape on a hole in the door, sprays a nearby cat with water causing it to run into the tape and stick fur to it, and uses some maple syrup from breakfast to make a fake mustache. The disguise inexplicably works, and Knight gets the bike.

Moreso than Le Serpent Rouge was praised, the disguise puzzle was roundly criticized for its lack of clarity, the impossibility of having Knight convincingly impersonate Mosely despite looking nothing alike, and the cartoonish roundabout way of Spoiler:making the mustache clashing with the game's serious tone. Critics felt that while it was not the most difficult puzzle, the solution was too absurd for the average player to think it would work. The most scathing review came from future Valve writer Eric Wolpaw, who blamed Jensen for the poor design (it was not known at the time that she did not design it), and called the process of Spoiler:making the mustache "deranged", controversially declaring it was proof that adventure games "committed suicide". While Jensen disliked the puzzle, she thought it being the death of adventure games was "kinda overblown", and the "length of the sequence and the lack of hints" was what made it bad.

RPG Maker 2003 allows developers to adjust the playback speed of an area's background music, something that Yume Nikki frequently makes use of. Several songs are featured in multiple areas, and in most cases, they are slowed down or sped up to fit a certain mood:

• The Mall Rooftop's background music is the Witch's Flight music played at 70% speed.
• The Sewers' background music is the Dense Woods A music played at 60% speed.
• The background music for each of the rooms in the Mall are the title screen theme played at 50% speed.
• The discordant noise heard when summoning Uboa in Poniko's house is the screeching that plays in the Guillotine Room played at 50% speed.
• The Teleport Maze's background music is the Aztec Rave Monkey's theme played at 50% speed.
• The Neon Tile Path's background music is the Snow World's music played at 70% speed.
• The Wilderness' background music is the ambient noise heard in the dream version of Madotsuki's apartment, played at 50% speed.
• The Face Carpet area in the Forest World uses the background music from the hot springs building hidden in the Wilderness, played at 70% speed.
• The background music heard in the entrance to the Mall is the background music from Shield Folk World, played at 50% speed.
• The Docks' background music is the background music heard in Mural World and Footprint Path 1, played at 50% speed.
• Puddle World's background music is Footprint Path 2's background music played at 50% speed.

Additionally, many unique area themes are played at a modified speed by default:

• The background music that plays in the underground area in Mars is played at 80% of its actual speed.
• The Pink Sea's background music is played at 60% speed.
• The ambient hum heard in Graffiti World and Hell is played at 60% speed.
• The ambient noise heard in Candle World is played at 50% speed.
• The main menu for the "Famitendo" in Madotsuki's room features music played at 70% speed.
• The ambient noise heard in the Mall and in Big Red's room is played at 50% speed.
• The gong chimes heard in Forest World are played at 50% speed.
• The ambient hum heard in the stairway leading from the Wilderness to the Sky Garden is played at 50% speed.
• The ambient noise heard in Ghost World is played at 50% speed.
• The ambient noise heard during the FACE event is played at 80% speed.
• The ambient noise heard in Number World is played at 50% speed.

Relatedly to the above, the chimes that make up Snow World's background music are also the same ones heard when interacting with jellyfish, played back at 110% speed for the first note and at normal speed for the second.

The game contains data for a second party member, despite the fact that Madotsuki is alone in standard gameplay. Using RPG Maker 2003's debugging tools to add this figure to Madotsuki's party shows that it does not have any sprites or even a name. However, various changes occur to the game's world, indicating that Kikiyama most likely used this for testing purposes:

• Almost all Toriningen are despawned; the only exceptions are the one in the Mall who changes the menu's palette when spoken to and the group throwing a party in the wilderness.
• The top-left cupboard in both versions of the Guillotine Room disappears. However, it can still be interacted with: pressing Z or Enter when standing where it normally would be transports Madotsuki to a random cupboard in the Number World, as if she had used one of the randomly generated exit cupboards. Returning to the Guillotine Room restores the top-left cupboard to its normal position.
• Movement is disabled upon waking up.
• The Witch's Flight event can be accessed by walking off the top-right corner of the Mall's rooftop, regardless of whether or not Madotsuki has the Witch effect equipped and active.
• An unused parallax background (named ネオン背景.xyz in the game's files) is enabled in Neon World, which normally has a solid black backdrop in Version 0.10 and all available early builds. This background, which depicts a series of ripples distorting a group of red, blue, and green lights, does not scroll correctly, only showing the top-left corner of it. Notably, this is the only unused background in the final game.

The notion that this invisible party member was used as a debugging tool is further bolstered by the presence of three similar extra party members (which also have no graphics or names) in Version 0.06. In that earlier build, Madotsuki is internally listed as the fourth party member; enabling the first one adds NASU to the game's debug map, though both that version and the one in Madotsuki's room will not progress past the title screen.

Scribblenauts Showdown is the first game in the series to not be developed by 5th Cell, the creators of the series. Instead, it was developed by Shiver Entertainment, and is notable for being the only original game developed by the company, with their other releases being Scribblenauts Mega Pack (a compilation consisting of Scribblenauts Unlimited and Scribblenauts Unmasked: A DC Comics Adventure) and the Nintendo Switch ports of Mortal Kombat 11, Mortal Kombat 1, and Hogwarts Legacy.

In all recovered early builds of the game, the Fat effect was provided by a funhouse mirror hidden in the large red maze (colloquially known as Hell). In Version 0.10, the mirror is removed and the effect is instead obtained by interacting with a tall, flashing humanoid (colloquially known as Strober) in the Docks B, and the portion of Hell where the mirror was once located is now empty. Incidentally, the Docks B is only accessible through Hell, preserving the association between the latter area and the effect.

Despite the mirror being removed from the normal course of play in the final build, it is still present in a debug room hidden in the game's code, functioning as it did in earlier versions. However, in the official English release, the text that appears when interacting with it, "★ふとる★", is corrupted due to it not being translated.

Within the files for the Version 0.04 build are cached thumbnails depicting screenshots from a cut soccer minigame called Severed Head PK, which, per its name, would've used severed heads as balls. Despite their small size, the thumbnails are legible enough to understand what they depict: one shows a title screen, one shows a player select screen, and one shows actual gameplay. Additionally, all three images feature a much cruder art style than either the main game or NASU, the minigame ultimately added in Version 0.06. Of note is that like Severed Head PK, NASU takes place in a green field beneath a black sky and prominently features bright red assets (hills, text, and the title logo in Severed Head PK; the player character, clouds, and a strobe effect in NASU).

Given that NASU is preceded by a game selection menu with only two options present – "NASU" and "Quit Game" (the latter of which simply closes the menu) – it is unknown if Kikiyama intended to reincorporate Severed Head PK as an additional option.

In 2020, to celebrate the launch of Shining Nikki in South Korea, Paper Games released a series of in-game wardrobe items based on the hanbok, a traditional Korean dress. This led to complaints from Chinese players, who objected to the hanbok being treated as a traditional Korean item and claimed that it was actually rooted in Chinese culture. On November 4, Paper Games released a statement supporting the argument that the hanbok was not Korean, and that "as a Chinese company, we want to reiterate that our stance is always consistent with our country China." They also announced that any accounts spreading misinformation about China or trying to insult the country would be blocked, implying that arguing that the hanbok was Korean counted as an offense. The hanbok items were ultimately removed from the game a day later.

This caused backlash from Korean players, who retaliated by deleting the game and applying for refunds for in-app purchases. On November 6, the game was delisted from Korean stores, resulting in demands that Paper Games be investigated for stealing Korea's cultural heritage and closing the service without offering compensation. This got to the point where Lee Sang-heon, a Democratic Party lawmaker from South Korea's National Assembly, called out Paper Games for siding with false claims from Chinese netizens and directing criticism towards Korean users. He also warned that their actions had violated South Korea's fair trade rules as they did not offer refunds and compensations prior to pulling the game from the country.

When asked if there had always been plans to make a Viva Piñata game for the Nintendo DS, producer Paul Machacek stated:

Concord is the first video game developed by Firewalk Studios, a company founded in 2018 as a subsidiary of ProbablyMonsters. Concord was originally made in collaboration between the two companies, but this changed in April 2023 after Sony Interactive Entertainment purchased Firewalk Studios, taking over development.

In a 2009 interview with IGN conducted to celebrate the franchise's 25th anniversary, series creator Alexey Pajitnov named the Game Boy version of Tetris as his favorite rendition, describing it as the closest approximation of what he first had in mind for the game.

In the original Dinosaur Planet, Krystal would come across a pachycephalosaurid dinosaur at CloudRunner Fortress, who is revealed to be one of the SpellStone guardians, who also gives Krystal the Illusion spellpage to bypass the SharpClaw guards within the dungeon. Z-Targeting him reveals his name to be "Gradabug", and that he is of the "BoneHead" tribe.

Gradabug would appear in the final Star Fox Adventures, with his role slightly rewritten as the chief engineer at CloudRunner Fortress (The Queen CloudRunner took over his original role as the SpellStone Gatekeeper for this area). While not mentioned anywhere in-game, the Star Fox Adventures Nintendo Power guidebook reaffirms him belonging to the BoneHead tribe.

In the PlayStation 4 and PlayStation 5 releases, Spoiler:Yuri's suicide is altered in order to comply with Sony's content guidelines. Specifically, Spoiler:her blood stains are changed from red to black, the animated blood splatters are replaced with static, the classroom background shifts to dark gray static, and the camera zooms in the first time she stabs herself. However, the following sequence, in which Spoiler:the player stays beside her corpse for several days, is unaltered.

Various Easter eggs are hidden in the game's character files, most of which require their extensions to be manually altered:

• If the player changes the extension for Monika's character file to .png, the resulting image depicts a square of white noise inside a ring of fire and cracks. Converting the white noise to binary gives a text message encrypted in Base64. Decrypting it reveals what appears to be a monologue from Monika, who mentions a "Third Eye" that causes "some kind of deja vu," which is how she and the other girls are able to perceive alterations to the game's data.
• If the player changes the extension for Natsuki's character file to .jpeg, the resulting image file depicts a painting of a white-haired girl with blank white eyes. The image is heavily distorted, requiring the player to invert its colors and change its rectangular coordinates to polar ones in an image editor in order to view it properly.
• If the player changes the extension for Sayori's character file to .ogg, the resulting audio will become a discordant shriek, similar to that normally heard when converting a data file to audio. However, running sayori.ogg through a spectrograph reveals a QR code which, when scanned, leads to a fictitious examination report for a character named Libitina; her last name and a procedure administered to her are both redacted with a series of X's. Of note is that like Monika's hidden monologue, the report repeatedly mentions a "third eye."
• If the player opens Yuri's character file in a text editor, the result will be a message encrypted in Base64; the file extension does not need to be modified in order to do this. Decrypting the message reveals that it's "I Found a Box Containing the Story of a 19-Year-Old Girl Who Killed a Random Person for No Reason", a creepypasta that was anonymously posted on Thought Catalog in June 2015, over two years before Doki Doki Literature Club's release. In a Twitter reply, developer Dan Salvato confirmed that he was the creepypasta's author and the one who hid it in the game.

The Givanium Citizens are primarily voiced by YouTubers who have played through the various games in the Garten of Banban series. Specifically:

• The Theater Witness is voiced by FusionZGamer.
• The Street Witness is voiced by Razzbowski.
• Jonasan is voiced by The Frustrated Gamer.
• Play Actor 2 is voiced by InquisitorMaster.
• The Dying Citizen is voiced by コロンボさん GAMES.
• The Apartment Witness is voiced by NightExtreme.
• The Ticketman is voiced by ORION (real name Brandon Zamora).
• The Bartender is voiced by UhYeah.
• The Strange Neighbor is voiced by Robzi.
• The Staring Citizen is voiced by IDzock.

In an Iwata Asks interview conducted to promote the release of The Legend of Zelda: Spirit Tracks, Takashi Tezuka revealed that the world of Link's Awakening was strongly inspired by the 1990 TV series Twin Peaks. According to Tezuka, he was fascinated by how the show was able to mine drama out of a small cast of "suspicious types" confined to a single town and sought to replicate that approach with Link's Awakening, stating that "while it would be small enough in scope to easily understand, it would have deep and distinctive characteristics."

One of the Sleep Mode screens, which depicts Mario and Luigi having a picnic in World 4-3, is based on a piece of concept art originally drawn for The Super Mario Bros. Movie, and was included in this Game & Watch over two years before the film's 2023 release. The original image is showcased in one of the bonus features on the film's home media release, "Meet the Cast: Charlie Day as Luigi". Among other differences, the concept art features Mario & Luigi sitting on mushrooms instead of blocks and wearing their modern outfits instead of ones matching their in-game sprites.